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PROCEEDINGS OF THE NATIONAL MUSEUM 



Gurney (1933) reported the cephalothoracic, abdominal, and f ureal 

 length as 90 : 40 : 20 ; the corresponding ratio for the specimens from 

 Erh Hai is 116 : 60 : 21. In other words, the cephalothorax in E. s. 

 serrulatus is 2.25 as long as the abdomen, while in E. s. extenstis it is 

 only 1.93 times as long. The subspecific name is suggested by this 

 relatively lengthened condition of the abdomen. Kiefer reported a 

 mean ratio of 5 : 1 for the length and width of the f urea among North 

 Indian and Tibetan females and a range of 4.5 to 6.3 ; the correspond- 

 ing values for Yunnan specimens are 5.62 and 5.5-5.7 (table 2). 



Six appendages ^ on each f ureal ramus : One slightly clorsally placed 

 lateral seta and one mesially placed dorsal seta, both slender and finely 

 plumose, one outer corner spiniform seta of about the same length 

 as the inner corner seta, which is slender and finely plumose and two 

 terminal setae with heteronomous plumage, inner terminal seta being 

 longer than the outer (7:5), dorsal seta only slightly shorter than 

 inner corner seta ; lateral seta least, only one-fifth as long as the dorsal ; 

 outer corner seta with very coarse serration on outer edge but finely 

 phunose on the inner. Last joint of endopodite of fourth leg three 

 times as long as broad, terminal spines on this joint subequal : inner 

 spine 1.23-1.29 times as long as the outer ; inner spine slightly longer 

 than the joint bearing it. 



The length-width ratio of the last joint of the fourth endopodite 

 for the Yale North India Expedition material has been given by 

 Kiefer (1939, table A). From the following comparative table it 

 will be seen that this structure is more slender in the Erh Hai 

 specimens (table 1). 



Table 1. — Measurements of last joint of endopodite of fourth leg of Eucyclops 

 serrulatus serrulatus and B. s. extensus 



^ In this paper the names for the caudal seta used by Harding (1942) have been adopted, 

 because they are more specific. The correspondence between his names and those of the 

 continental workers follows: Outer corner seta = seta of the outer edge; inner corner 

 seta = innermost apical seta; inner and outer terminal setae = two middle setae. 



